The evaluation of propulsion systems and projectile velocity includes the need to decelerate projectiles in a safe manner and over a short distance without causing harm to the projectile or to the environment. One such method which has been used is to fire the projectile into a large quantity of water, somewhat like shooting a bullet into a barrel of water. Of course, the bullet is deformed when it strikes the water, and thus cannot be reused.
More sophisticated systems have been designed to capture larger projectiles, but it has been found that the apparatus needs to be extensive in size. Moreover, concern must be given to confining the water or other fluid to prevent causing hazardous working conditions. More importantly, a device for directing the projectile into the water or other fluid often causes damage to the projectile because of the impact of the projectile on water. Water is clearly the fluid of choice, due to its clarity, availability, and safety.
Nevertheless, water is relatively incompressible. This allows for hydraulic forces to assist in decelerating the projectile but also causes an initial impact to potentially damage the projectile, particularly at high energy levels of up to about 650,000 foot-pounds. To date, no satisfactory system has been designed which permits deceleration of such high energy projectiles without damage and great inconvenience.
In some instances, the operation of devices presently available causes such damage to the device due to the force of impact of the projectile on the fluid that no really meaningful data can be obtained. To date, no effective device has been proposed which can decelerate high energy projectiles in short distances which permit operation in normal or conventional sized rooms and buildings.
Accordingly, it is an object of this invention to provide a device for decelerating high energy projectiles with complete safety for the projectile and for the environment and workers in the area.
Another object of this invention is to provide a device for decelerating high energy projectiles which can operate in relatively short distances of no more than about 20 feet in length.
Still another object of this invention is to provide a device for decelerating high energy projectiles which can be used with water as the decelerating medium, where the water is contained in a closed system.
Other objects will appear hereinafter.